The overall objective of this research is to broaden our knowledge on the pathogenesis of acne vulgaris, as well as to elucidate the action of current treatment modalities on this disease. The follicular cast, which represents a pre-comedone, and can be obtained by non-invasive means will be extensively examined. Development of pre-comedones will be followed by correlated structural, microbiological, lipid, and inflammatory studies of follicular casts obtained during a longitudinal study of prepubital children. Similar correlated studies will be performed on follicular casts obtained from subjects with acne before, and after various treatment regimes in an effort to better understand the action of currently used therapeutic modalities.